Advice explainer: Cantabrian and Atlantic Iberian sardine

We take a look at some of the key points contained within the advice recently released for sardine in divisions 8.c and 9.a (Cantabrian Sea and Atlantic Iberian waters) in the Bay of Biscay and Iberian Coast ecoregion.

Published:
20 October 2017

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​​​​​​​​What does the advice say?

For many of its stocks, including this one, ICES issues advice according to a maximum sustainable yield (MSY) approach, which aims at achieving the largest catch (in tonnes) over the long term while keeping the stock in a healthy condition. This is done in accordance with international agreements.

Why has the MSY approach been used this time?

Advice for this stock has previously been given in line with an EU long-term Iberian sardine management plan. In 2016 ICES was requested to examine whether introducing an adjustment to the plan would be precautionary.

After evaluation, the plan was found to be not precautionary​, meaning the proposed adjustment was no longer relevant. Because of this, ICES no longer uses the management plan and has instead applied the MSY approach.

Why was the management plan found to be not precautionary?

The management plan was evaluated taking into account the new assessment model adopted for this stock in early 2017. Although the new model better fits the data, it did not significantly change the picture of stock abundance or exploitation. The development of biological reference points, however, revealed that the stock is presently below the biomass limit (a marker known as Blim).

Recruitment (a key component of stock productivity) has declined over time and has been especially low since 2006. Data on stock recruitment from 1993-2015 were used to determine likely future recruitment in the evaluation of the plan. Given this level of recruitment, the probability of rebuilding the stock biomass to above the Blim limit within five years is low and, in the long term, considerably less than the 95% normally required.

Along with the advice, some additional details were offered on the future development of the stock, where it was indicated that rebuilding to above a safe biomass limit with a high probability (above 95%) could take around 15 years with no fishing. This is assuming that the low stock recruitment estimated for 1993-2015 continues in the future. A precise time span for recovery cannot be given, as it is unknown how long the low productivity will continue.

Why was the advice delayed to October?

Due to logistical issues with the Portuguese spring acoustic survey, 2017 data could not be processed for the usual advice timing in July. This has now been resolved, and these data are included in the stock assessment and advice.

What is the basis for advising zero catch in 8.c and 9.a in 2018?Numbers of young sardine joining the stock are low, reflected in recruitment and productivity rates, and the stock biomass is substantially below Blim. The limit biomass level cannot be reached in 2019 even without any catch in 2018. Zero catch is therefore advised for 2018 in order to help the stock recover.